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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 2811-2817 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: When hexaphenylcyclotrisilazane was heated above 450°C. at atmospheric pressure, it formed an infusible polymer of exceptional thermal and chemical stability. The polymerization, which was accompanied by elimination of benzene, is represented approximately by the equation: \documentclass{article}\pagestyle{empty}\begin{document}$\eta [({\rm C}_6 {\rm H}_5)_2 {\rm SiNH}]_3\,\, \to \,\,({\rm C}_6 {\rm H}_5 {\rm SiN})_{3n} + 3n{\rm C}_6 {\rm H}_6$\end{document} The infusible polymer was a foamed, vitreous, pale yellow solid with a high degree of stability to heat, acids, alkali, and organic solvents. A similar reaction occured with a resein that was obtained as a by-product in the preparation of hexaphenylcyclotrisilazane and with a mixture of silylamines that was obtained from the reaction of methylphenyldichlorosilane with ammonia. Coatings on aluminum and steel prepared by heating the silylamine polymers had good thermal stability and adhesion. Inclusion of a polymeric dimethylsilyl derivative of ethylenediamine improved the flexibility of the coatings.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Advanced Materials 3 (1991), S. 343-350 
    ISSN: 0935-9648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A New class of highly electroactive hydride-forming compounds is described as well as simple metallurgical methods for producing these materials. The new type of metal alloys consist of two different crystallographic phases. The bulk phase is responsible for hydrogen storage and is formed by the stable multicomponent “standard alloy” of the AB5 type. The second phase homogeneously decorates the surface of the bulk phase and ensures a high electrocatalytic activity. In composing this second phase no precious metals are required, but carefully selected combinations of transition metals can be used. Very high overall exchange currents and discharge efficiencies are obtained, even at low temperature. Cycle life and storage capacities are comparable with the values found for the standard alloy. Substituting small amounts of B-metals with highly electrocatalytic elements was also found to be effective in improving the electroactivity of AB5 compounds. However, a drawback of this method is that significant improvements are obtained only when precious metals are incorporated. Double-phase materials must therefore be considered as more serious candidates for use in future nickel/metal-hydride batteries with high charge/discharge capability.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The role of certain inorganic salts in increasing the flux of water through semipermeable membranes of cellulose acetate is related to the capacity of the component ions to swell the cellulosic substrate. The mechanism whereby ions which are high on the Hofmeister lyotropic series swell and dissolve secondary cellulose acetate has been investigated. Swelling is effected by the formation of metastable complexes involving the highly hydrated cationic fraction of the salt and both the hydroxyl and acetate groups of the cellulose acetate. Whereas effective anions possess large ionic radii and cause a breakdown in the structure of water which results in increased hydration of the cation, ineffective anions possess higher charge densities and tend to pair with the cation and decrease the latter's electrophilicity and hence hydratability. Ionic charge density is the factor of prime importance both with respect to the hydratability of the cation and the tendencies toward water disaggregation and ion association of the anion. The mechanism involved in the swelling of secondary cellulose acetate is related to swelling phenomena in many other polymers containing polar groups.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The mechanism by which water and dissolved salts permeate selectively through membranes has been investigated. It has been demonstrated that the predominant mechanism of permeation involves the interaction of the various species with specific sites and their associated bound water molecules. The extent of the bound water held by the cellulosic membranes of interest has been determined. Correlation has been found between the permeation characteristics demonstrated by membranes at various steps in their preparation and its bound water content. The mechanism of rejection of salts has been shown to be related to the relative inability of their ions to become solvated by bound water. A model has been hypothesized which correctly describes the behavior of the desalination membrane with reference to water and soluble inorganic salts.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A quantitative study has been made of the effects on the membrane gel structure of parameters whose significance with respect to desalination performance had previously been empirically established. The composition of the polymer solutions, the fabrication temperatures, and the pressure employed during desalination are shown to be related, in that they all influence the swelling behavior of the gel structure. The relationship which has been found between the water content and the rate of water transport across semipermeable membranes of cellulose acetate is explained on the basis of a solution transport mechanism.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 247 (1997), S. 61-72 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: UV stabilization of polymer systems containing brominated flame retardants has proven to be a difficult technical challenge. Generation of acidic products during processing or exposure can cause a catastrophic deactivation of the Hindered Amine Light Stabilizer (HALS). An understanding of the mechanism for bromine generation from aliphatic and aromatic based flame retardants has lead to formulation approaches based on flame retardant structure. In formulations containing aromatic brominated flame retardants, combinations of UV absorbèrs and a new class of siloxane HALS provide the highest level of UV stabilization to date. Alternatively, bicomponent fiber spinning technology can also provide outstanding UV resistance at significantly lower levels of stabilizers than that used in the monocomponent formulation approach.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 26 (1988), S. 1313-1329 
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The miscibility of polyester/nitrocellulose blends was investigated by differential scanning calorimetry and Fourier-transform infrared (FTIR) spectroscopy. Two nitrocelluloses (NC) derived from wood and having different nitrogen contents (12.62 and 13.42%) were used. On the basis of the glass transition temperature criterion, poly(∊-caprolactone) (PCL), poly(valerolactone), poly(ethylene adipate), and poly(butylene adipate) are miscible with nitrocellulose, whereas poly(α-methyl α-propyl β-propiolactone) and poly(α-methyl β-proiolactone) are immiscible. The Tg versus composition curves of PCL/NC blends do not follow a monotone function but exhibit a singular point at a critical PCL volume fraction of 0.51 for NC-1342 and 0.45 for NC-1262 in agreement with Kovacs' theory. A shift of 17 cm-1 of the carbonyl stretching band was observed with PCL/NC blends and is taken as evidence for hydrogen bonding interaction between the PCL carbonyl group and NC hydroxyl group. The frequency difference between the free hydroxyl absorbance and the absorbances of the hydrogen-bonded species was found to be 85 cm-1 in pure NC and 125 cm-1 in PCL/NC blends; it indicates that the average strength of this interaction is stronger than the corresponding self-associated hydrogen bonding in pure NC. The presence of a dipole-dipole interaction between the nitrate-ester groups of NC and the carbonyl groups of the polyesters is reported. The relative strength of the hydrogen bonding and dipole-dipole interactions is discussed and correlated with polymer miscibility.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 26 (1988), S. 1769-1780 
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Flory equation-of-state theory, as expressed by Patterson and co-workers, has been applied to two miscible polymer blends: poly(vinyl chloride)/poly(ε-caprolactone) and poly(methyl methacrylate)/poly(vinylidene chloride). For both blends, the variation of the polymer-polymer interaction parameter, χ′23, as a function of composition, is mostly small and can be accounted for by the Flory theory. However, for poly(vinyl chloride)/poly(ε-caprolactone) blends, at high poly(ε-caprolactone content), the large variation of χ′23 as a function of concentration can be explained by a variation of the surface-to-volume ratio of the polymers in the mixture with blend composition. The variations of the surface-to-volume ratios determined in this study agree with those reported in the literature using small-angle x-ray scattering.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 28 (1990), S. 1283-1296 
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Fourier-transform infrared (FTIR) spectroscopy has been used to investigate the segmental orientation of poly(vinyl chloride) (PVC)/poly (α-methyl-α-n-propyl-β-propiolactone) (PMPPL) blends in uniaxially stretched samples over a wide range of compositions and draw ratios. The results indicate that for pure PVC, syndiotactic segments reach a higher degree of orientation than isotactic segments and gauche conformations. Similarly, for pure PMPPL, crystalline segments orient more than amorphous segments at any given elongation. Thus, for both polymers, the higher orientation is obtained for the more rigid segments or those located in a more rigid (crystalline) phase. The addition of the macromolecular plasticizer PMPPL has no effect on the orientation of PVC syndiotactic segments, but it lowers the orientation of PVC gauche conformations, suggesting that the polyester is located in the amorphous regions of PVC. Finally, the PMPPL orientation function initially decreases with the addition of PVC and thereafter remains constant. The results are discussed in terms of interpenetrating networks and relaxation processes.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 24 (1986), S. 2565-2582 
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymer/polymer interaction parameters χ′23 have been measured at 120°C as a function of polymer concentration for six different poly(vinyl chloride)/linear aliphatic polyester blends. The technique used is inverse-phase gas chromatography with several molecular probes. The polymers investigated are poly(DL-lactide), poly(ethylene succinate), poly(ethylene adipate), poly(butylene adipate), poly(δ-valerolactone), poly(ε-caprolactone) and poly(hexamethylene sebacate). Probe/polymer interaction parameters χ12 and polymer/polymer interaction parameters χ′23 values are dependent upon the methylene to carbonyl ratio of the polyester, reaching a minimum for a value of 5, this ratio corresponding to poly(ε-caprolactone) blends. Results are interpreted in terms of pairwise interactions between carbonyl, methylene, and [CHCl] groups.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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